High-pressure light source having inclined tangential gas supply passages



cmsrzm-zuca suncn ROOM Oct. 8, 1968 D. G. VAN ORNUM ETAL 3,405,314

HIGH-PRESSURE LIGHT SOURCE HAVING INCLINED TANGENTIAL GAS SUPPLY PASSAGES 2 Sheets-Sheet 1 Filed Nov. 18, 1963 Oct 8, 1968 D. G. VAN ORNUM ETAL 3,

HIGH-PRESSURE LIGHT SOURCE HAVING INCLINE!) TANGENTIAL GAS SUPPLY PASSAGE-S Filed Nov. 18, 1963 2 Sheets-Sheet 2 ATTOQA/EFS United States This invention relates to apparatus and methods for generating high-intensity light by means of an electric arc. The invention further relates to an apparatus and method for transmitting intelligence through use of a light beam. This application is a continuation-in-part of our co-pending patent application Ser. No. 203,760, filed June 20, 1962, for Light Source and Methods, now abandoned.

The present invention constitutes an improvement over the inventions described and claimed in co-pending patent application Ser. No. 200,584, filed June 6, 1962, for a Lamp Apparatus, inventors Gabriel M. Giannini, Adriano C. Ducati and Hubert C. Sullivan, now abandoned, and in patentapplication Ser. No. 197,097, filed May 23, 1962, for an Electrical Discharge Apparatus and Method for Achieving High Temperatures and Mach Numbers, inventor Adriano C. Ducati, now abandoned.

An object of the present invention is to provide a light source apparatus and method wherein all portions of the arc chamber contain gas under high pressures, with resulting great increases in such factors as eificiency electrode life, and brightness.

An additional object is to provide a high-intensity light source and method characterized by improved electrode configurations shaped and disposed to permit extraction of the maximum amount of light energy from the arc, and to achieve optimum vortex conditions, in combination with means to achieve a highly effective stabilization of the are passing between the electrodes.

An additional object is to provide an extremely effective and efiicient light source and method adapted to be employed for a wide variety of purposes including solar simulation, re-entry simulation, spectroscopy, laser pumping, intelligence transmission, black-body radiation; etc

Another object is to provide an apparatus and method for modulating an electric-arc light source whereby the are and resulting plasma are caused to transmit speech, code or other intelligence, and further to provide a method and apparatus for detecting and interpreting such intelligenceat a point remote from the light source.

These and other objects will become apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIGURE 1 is a longitudinal central sectional view illustrating the present light source;

FIGURES 2 and 3 are transverse sectional views taken respectively on lines 22 and 3-3 of FIGURE 1, and illustrating means to introduce gas tangentially into the arc chamber;

FIGURE 4 corresponds to FIGURE 1 but illustrates the forced-recirculation means, and also illustrates a means to modulate the arc to impart intelligence thereto; and

FIGURE 5 illustrates schematically one form of apparatus for sensing the intelligence transmitted by the apparatus shown in FIGURE 4.

Referring first to the light source shown in FIGURES 1-3, the apparatus is seen to comprise an elongated transparent or light-transmissive tube formed of quartz glass, fused silica or the like. Extended into opposite ends ice of tube 10 are electrode assemblies 11 and 12, such assemblies having opposed arcing portions 13 and 14, respectively. The arcing portions, which may comprise inserts of thoriated tungsten or the like, are arranged at the axis of the arc chamber 15 defined within tubing 10. It follows that a high-current electric are or spark may be maintained between the arcing portions 13 and 14, such arc being gas-vortex stabilized along the axis by means of gas which is introduced tangentially into arc chamber 15 as will be described subsequently.

The electrode assembly 11 illustrated at the left in FIGURE 1 may comprise a generally cup-shaped copper body 17 having an elongated tubular stem or center portion 18 which extends into the tubing 10, there being a suitable sealing sleeve 19 provided between portion 18 and tubing 10 to prevent leakage of gas from the arc chamber. Tubular portion 18 defines within it a coolant chamber 21 the outer end of which is closed by a plate or disc 22 which is suitably secured to the outer end of body 17. The inner end of coolant chamber 21 is closed by a generally conical electrode element 23 having the aboveindicated arcing insert 13 mounted at the apex portion thereof. Suitable means, including sealing rings which prevent leakage of water or other coolant from chamber 21, are provided to associate plate 22 and electrode element 23 with opposite end portions of the tubular portion 18. Other suitable means, including a seal-mounting sleeve 24 and a bolted-on retaining ring 25, are provided to associate the wall of cup-shaped body 17 with the end portion of the transparent tubing 10.

A pipe or tube 27 is inserted longitudinally into the coolant chamber 21 to introduce water therein at a point relatively adjacent the conical electrode element 23, such water then passing outwardly through the coolant chamber and through a discharge conduit or pipe 28. Other conduits or passages are formed through the tubular portion 18 of the copper body 17 in order to introduce gas tangentially into arc chamber 15. Referring to both FIG- URES 1 and 2, three passages 30-32 are formed longitudinally through the tubular body portion 18 and communicate respectively with pipes 33-35 leading to a suitable source 36 of gas under pressure. The passages 30-32 turn right-angled corners, as shown in FIGURE 2, so that they will enter the arc chamber 15 tangentially through the tangential passages portions 37-39. Such portions emerge from tube 18 at a beveled or frustoconical inner end portion 41 thereof and which is generally flush with the external surface 42 of the electrode element 23.

The electrode assembly 12, shown at the right in FIG- URE 1, comprises an elongated copper body 44 having a reduced-diameter tubular extension 45 which is inserted into the transparent tube 10 as in the case of the portion 18 of electrode assembly 11. The relationship of copper body 44 and its extension 45 relative to quartz tube 10 is substantially the same as was described relative to the assembly 11. Thus, a sealing sleeve 19a, seal-mounting sleeve 24a and retaining ring 25a are provided.

At the inner end of the tubular extension 45 of body 44 is mounted a generally conical electrode element 46 having a conical outer surface 47. Such surface is general- 1y flush with the frusto-conical surface 48 at the inner end of extension 45. Means are provided to feed gas through extension 45 into arc chamber 15, and may correspond exactly to the previously described means 30-39, the tangential inlet passages being directed in the same direction as the inlet passages 37-39. Thus, three passages 50-52 are fed with gas from pipes 53-55 leading to a suitable gas source 56. The passages terminate in the tangential inlet portions 57-59.

The combined cross-sectional areas of passages 37-39 and 57-59 are less than the cross-sectional area of the outlet passage for the plasma, namely the area of a passage through arcing insert 14.

It is pointed out that the cone angles of the electrode surfaces 42 and 47, and their cooperating frusto-conical surfaces 41 and 48, correspond generally to each other. Such angles are on the order of thirty to sixty degrees from the axis of the arc chamber 15. The cone angles should not be so large that a substantial amount of light generated by the electric arc or spark (including the footpoints thereof) which passes between arcing portions 13 and 14 is prevented from radiating through the lighttransmissive wall means 10.

It is a feature of the light source that the interior surface of the quartz tube (which is a surface of revolution about the axis of chamber 15) is maintained clean and cool by the vertically-flowing gas which is introduced into the arc chamber 15 as described above. Such gas is heated by the arc and then is discharged axially through the electrode element 46. The gas or plasma is then cooled and suitably recirculated to the gas source or sources 36 and 56. It is to be understood that the sources 36 and 56 may be combined, and that they may be eliminated and replaced by pump means communicating with the conduit means through which gas passes outwardly from are chamber 15. Such a recirculator is shown at P in FIG- URE 4, the gas-outlet means being indicated at O and the inlet means at I.

The plasma generated in arc chamber 15 discharges through the arcing insert 14, which is tubular in shape, and then passes into a tubular stem portion 61 of the electrode element 46. Such stem is sealingly connected to an elongated metallic tubular conduit 62 which extends through the end plate 63, the latter corresponding to the plate or disc 22 of electrode assembly 11. The end plate 63 is adapted to sealingly close the outer end of concentric outer and inner coolant chambers 64 and 65 which are separated by an elongated tubular bafiie or divider element 66. Element 66 extends from the end plate 63 to a region relatively adjacent the interior surface of electrode 46, at which point communication is effected between the chambers 64 and 65 so that water may flow in series there" through.

Water is fed into the outer chamber 64 by means of a pipe 67, from whence it flows around the inner end of divider 66 to the inner chamber 65 and thence to a discharge pipe 68. In this manner, the electrode 46 and also the stem 61 and conduit 62 are effectively cooled. It is pointed out that the conduit 62 and associated coolant chambers may be of any desired length, in accordance with the degree to which it is desired to cool the plasma prior to discharging or recirculating it. An effective predetermined heat-exchanger action is thus achieved.

Description of the method, embodiment of FIGURES 13 In performing the method with the light source illustrated in FIGURES 1-3, the electrode assemblies 11 and 12 are adjusted axially of the transparent tube 10 until the arcing inserts 13 and 14 are spaced at predetermined desired distance from each other. Such distance is preferably between about 3 millimeters and about millimeters. If the electrode spacing is excessively short, much of the radiation is lost or ineffective because of shielding by the electrodes. On the other hand, a long distance between the electrodes makes it difficult or impossible to achieve adequate vortex conditions. Furthermore, a long arc creates severe optical problems relative to transmission of the generated light.

The gas sources 36 and 56, or the pumping means (such as pump P, FIGURE 4), are then utilized to introduce inert gas through the various conduits, passages and tangential passage portions 37-39 (FIGURE 2) and S7- 59 (FIGURE 3). Such inert gas may comprise, for example, argon, xenon, neon, krypton, helium, or mixtures thereof. One such mixture may comprise argon and xenon. The gas flows vertically in the arc chamber 15 and then discharges through the insert 14, stem 61 and conduit 62. The various factors are so selected that the gas pressure within arc chamber 15 is high, many times atmospheric, being preferably at least 100 p.s.i. absolute. A preferred pressure is about 250 p.s.i. absolute or much higher, since black-body radiation is then approached or achieved.

The pressures stated in the preceding paragraph are the pressures at the axis of arc chamber 15, that is to say the pressures in the canal through the vortically-flowing gas. The maximum pressures in the arc chamber are in each instance much greater than the pressures at the axis, the pressure differential being sufficient to create an effective and efiicient vortical flow of gas. Thus, for example, the maximum chamber pressure should be at least 30 p.s.i. higher than the pressure at the axis, and is preferably 60 or more p.s.i. higher than the pressure at the axis.

An electric arc or spark is initiated between the inserts 13 and 14, through use of a current source 70 and associated leads 71 and 72, which are connected to the respective electrode assemblies 11 and 12. It is to be understood that such leads may be associated with the water conduits, so that they are water cooled. Furthermore, and very importantly, it is to be understood that the current source 70 may be adapted to supply direct current, single or multi-phase alternating current, compound direct and alternating current, or pulses of current. Thus, for example, source 70 may comprise a capacitor bank and appropriate triggering apparatus. Where source 70 is a DC. source, insert 14 is preferably positive and insert 13 negative.

In apparatus wherein source 70 is of the steady-state type, means are provided to initiate the are between the inserts 13 and 14. In the present apparatus, such means is illustrated to comprise an elongated electrode 73 surrounded by an insulating sleeve 74. The tip of the electrode 73 is disposed relatively adjacent insert 13 but out of contact therewith. To start the are between inserts 13 and 14, current source 70 is applied following which a pulse of high voltage is impressed between the electrode 73 and one of the electrode assemblies 11 and 12. A spark is thus generated therebetween, such spark ionizing the gap between inserts 1'3 and 14 and serving to initiate the main arc. It is to be understood that elements 73 and 74 may be omitted, as in FIGURE 4, in which case other suitable starting means are employed.

The current source 70 is caused to supply a large current, for example on the order of 300 amperes or more. The voltage between the inserts may be on the order of 20 to 200 volts, or higher, depending on factors such as the gas pressure and the spacing between the inserts. The rate of the gas flow passing through the arc chamber 15 may be, for example, about one standard cubic foot per minute up to ten standard cubic feet per minute, such rate being given for argon gas.

The are is gas-vortex stabilized and constricted between the inserts 13 and 14, so that the visible portion of the arc extends along a straight-line path coincident with the axis of chamber 15. Furthermore, the verticallyflowing gas efiiciently cleans and cools the interior wall of the glass tube 10, it being pointed out that any impurities or contaminants removed from the electrodes are discharged through the insert 14 instead of contacting the transparent tube. The vortically-flowing gas also rotates the arc footpoint which engages the electrode assembly 12.

It is to be understood that the arc extends axially, along a straight line, from the tip of arcing insert 13 into the central passage in electrode assembly 12 (including the passage in insert 14). The arc then bends outwardly into contact with an interior wall portion of assembly 12, th point of contact being termed the footpoint.

It is essential to the present invention that the gas pressure in all portions of the arc chamber 15 be high, as previously indicated. When the gas pressure along the axis of arc chamber 15 is high, a relatively large number of molecules are present and accordingly, when excited, emit a large amount of very bright light. Furthermore, the high gas pressure along the axis means that the voltage impressed between the electrodes is much greater than in apparatus wherein the gas pressure along the axis is on the order of atmospheric. Since the voltage is high, the arc current may be relatively low and yet achieve a predetermined total are power. Thus, a given quantity of light may be generated with a much lower arc current, and consequent much lower rate of electrode erosion, than in apparatus wherein the pressure along the axis is low. In summary, therefore, the present high-pressure system operates very effectively and efficiently, and for a much longer period of time without excessive electrode erosion, than dolight sources in which the canal through the vortically-flowing gas is at low pressure.

It is essential to the vortex-stabilized radiation source that a highly efficient vortex be generated, with a very steep pressure gradient adjacent the axis of the arc chamber 15. As previously indicated, the pressure differential between the relatively high pressure at the axis and the even higher pressure adjacent the inner surface of envelope must be suflicient to effect rapid vortical flow of the gas. The following factors cooperate to create the necessary vortex condition in the present apparatus:

(a) The pressure differential between the axis and portions of the chamber remote from the axis is substantial, being at least on the order of 30 psi. as previously stated.

(b) The outlet opening from the chamber 15 is at or very near the axis thereof.

(0) The cross-sectional area of the outlet from cham ber 15 is substantially greater than the combined crosssectional areas of the inlets.

(d) The gas is introduced into chamber 15 at a sub stantial number of points.

(e) The conical shape of the electrodes reduces the volume (and inertia) of the gas which must be whirled within the chamber 15.

(f) The relatively close electrode spacing reduces the volume of the gas which must be whirled, and lessens the distance axially of the apparatus between the gas inlets and the arc itself, so that efiicient vortical flow conditions may be maintained.

It is also highly important to the vortex-stabilized source that a substantial blanket of cool, clean gas be present between the arc and the interior surface of tube or envelope 10. If the tube diameter is small, no such cool and clean blanket is present since heat transmission from the are results in excessive heating of all of the gas within the arc chamber, and since the entire gas blanket becomes contaminated with electrode material. The envelope then becomes clouded, overheated and eroded. In the high-pressure high-power vortex-stabilized light source of the present invention, the inner diameter of the envelope must be substantially greater than the distance between the electrodes, preferably a plurality of times such distance. Thus, for an electrode spacing of 10 millimeters, the inner diameter of the envelope may be 25 millimeters. The present source is to be contrasted with relatively low-pressure sources, in which the power is relatively low and the envelope diameter is small.

An important advantage of the gas-vortex stabilized source is that the brightness is increased in comparison to other systems, even systems operating at the same pressures, for example those in which the gas flows axially of the arc. It is emphasized that cool gas is highly transparent, as is the envelope 10. However, the boundary layer between the hot arc and the cool gas is absorptive, due to its excited condition, and absorbs a substantial amount of the radiation from the arc. Thus, it is necessary that the boundary layer between the cool gas and the arc be thin, the degree of absorption varying directly with thickness. In the present light source, the boundary layer is much thinner than in other light sources, such as those wherein gas flow is axial, so that the degree of brightness of the present source is high. It is pointed out that a vortex formed of whirling water is not satisfactory, one reason being that the ultraviolet and infrared components are screened out of the emitted light.

A further significant advantage of the gas-vortex stabilized light source is that very high power levels may be achieved in a small apparatus. For example, initial prototypes designed for operation at 25 kilowatts proved to operate satisfactorily at kilowatts. Such an increase in power level, by a factor of four, is highly surprising. It is important that the apparatus be small, since large apparatus "shields (blocks) a large proportion of the generated light.

Another advantage of the gas-vortex stabilized source is that the diameter of-the arc column may be varied by altering gas flow conditions. It will be understood that even with a high power level the arc diameter may be made very small if the gas flow conditions are properly selected. It is emphasized that a very small-diameter (and relatively short) stable arc is desirable in that a point source of light is simulated.

The vertically-flowing gas provides the further advantage of cooling the electrode tips efi'iciently. It follows that the electrodes may be relatively pointed, so that a wide angle of light transmission results. Stated otherwise, the electrodes may be so shaped that they block only a relatively small proportion of the generated light, The conical surfaces of the electrodes described herein, having relatively steep cone angles, do not block light since the conical surfaces are in the shadows of the electrode tips. Such conical electrodes improve the vortex action (as stated previously), and permit maximum water cooling of the electrodes.

The plasma generated by the arc is efficiently cooled during its passage through the long water-cooled conduit 62, such conduit being sufficiently long (for example a number of feet) to achieve the desired degree of cooling. The conduit may be coiled to conserve volume (or other heat exchanger techniques may be used, such as filling the conduit with sintered copper). The gas is then recirculated by the pump means P (FIGURE 4) to the inlet pipes 33-35 and 53-55. Suitable filter means are incorporated in such recirculation means in order to remove contaminants prior to re-introduction of the gas into arc chamber 15. Such a filter means" is shown at F in FIGURE 4.

Apparatus and method for transmittiriand receiving intelligence through use of light sour' ies of the present type There will next be described a method and apparatus for transmitting and receiving intelligence through use of the present type of light source. Reference is made to FIGURES 4 and 5.

Referring to FIGURE 4, intelligence may be imparted to the are by modulating the current source 70, such as through use of the modulator 116 which is connected to the source 70 through a switch 117. The modulator 116 may, in turn, receive intelligence from any suitable source such as the indicated microphone 118 adapted to receive speech.

It is to be understood that the microphone 118 may be replaced by other suitable means such as a source adapted to generate Morse code pulses. Stated otherwise, pulses are superimpowd on the steady-state arc.

The modulated light created as described above is transmitted to a remote point. Referring to FIGURE 5, a photosensitive pickup 121 is disposed at such remote point and receives the light signal. Pickup 121 is connected to a demodulator 122 which in turn feeds into a suitable simplifier 123 and an output means such as a loudspeaker 124 (in those instances where the input is speech into a microphone). In this manner, the speech 7 introduced into microphone 118 (FIGURE 4) is reproduced in the loudspeaker 124 (FIGURE It is pointed out that the modulation of the arc maintained between inserts 13 and 14 (FIGURE 4) may also be effected directly by magnetic means. Thus, a magnetic coil may be mounted around the end of at least one of the inserts 13 and 14 and supplied directly with modulating current from the modulator 116. Magnetic modulation of the arc is thus achieved. It is pointed out that the modu= lating coil or coils are disposed at such locations that they do not substantially block the radiation of light from the arc through the wall means 10.

The following is a summary of certain of the above, and other, important advantages which are achieved relative to vortex-stabilized light sources constructed in accordance with the present invention:

(1) The source is very bright and efficient, and has a very long life.

(2) The cool vortex flow continually replaces the gas surrounding the are, thus greatly reducing red and infrared radiation as compared to the radiation from other enclosed arcs. The boundary layer between the arc plasma and the surrounding cool gas is very thin, thus producing the important advantage stated heretofore.

(3) The vortex fixes the arc plasma diameter (constricts the arc), and precisely locates the are or spark column. By varying the gas-flow conditions, the diameter of the arc column may be varied.

(4) The vortically-flowing gas maintains the Window relatively clean and cool.

(5) The source will operate at Surprisingly high power levels, and through a wide range of power levels.

(6) The vortex effectively cools the electrodes, permitting the structure to be such that wide angle of light may be transmitted.

(7) Spectral energy distribtuion may be varied by employing different gases or mixtures thereof, and by changing the pressure of the gas.

(8) The source will operate in any attitude and in any environment, such as in sea water or in a vacuum.

As a specific example, relative to the first embodiment of the invention, operated on DC power, the arc plasma was 10 millimeters long by 3 millimeters in diameter. The input power was 24.8 kilowatts at a chamber pressure of 17 atmospheres, so that the plasma temperature was approximately 7,000 degrees Kelvin. The useable radiation solid angle was 10 steradians, and a luminous output of 42,200 candles was generated. The average brightness was 140,000 candles per square centimeter, the luminous efliciency being 17 lumens per watt. The total radiant output, luminous and non-luminous, was 7.68 kilowatts radiant flux, making the over-all efficiency 30%. The ultraviolet output (200 to 400 millimicrons) was 2.6 kilowatts radiant flux.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited We claim:

1. Apparatus for generating high-intensity light, comprising:

wall means to define an arc chamber,

at least a major portion of said wall means being a surface of revolution about a central axis,

at least a portion of said wall means being lighttransmissive to permit light to emanate from said chamber,

passage means inclined relative to said axis to introduce directly and generally tangentially into said chamber, for flow vortically about said axis, a relatively cool, inert gas having a pressure of at least 100 p.s.i.a. at said axis,

means to discharge gas from said chamber along said axis, and

means to create in said chamber along at least a portion of said axis a high-current electric are or dis charge,

said are or discharge being stabilized by said gas and generating light for transmission through said light-transmissive portion of said wall means.

2. A high-intensity light source, which comprises:

an elongated light-transmissive tube,

first and second elongated electrode assemblies extended axially into opposite ends of said tube,

said assemblies having arcing portions disposed opposite each other coaxially of said tube,

the distance between said arcing portions being substantially smaller than the inner diameter of said tube,

at least one of said electrode assemblies having a gas-discharge passage formed therethrough and communicating directly with the axis of the arcing portion thereof,

said assemblies cooperating with said tube to define an arc chamber,

passage means in at least one of said electrode assemblies and having passage portions oblique to the axis of said tube to introduce a cool, inert gas tangentially into said are chamber at a point located farther from said axis than said arcing portions, and at a pressure which is at least p.s.i.a. at said axis, and

means to maintain between said electrode assemblies and along said axis a high-current electric arc,

said are being stabilized by said gas and generating light which is transmitted through said tube,

3. A method of generating high-intensity light, which comprises:

providing a cavity having a transparent Wall which is a surface of revolution about a predetermined axis, maintaining along at least a portion of said axis a high-current electric arc,

introducing continuously into said cavity, at a location remote from said arc, a relatively cool gas selected from a group consisting of argon, xenon, neon, helium, krypton and mixtures thereof,

effecting vortical flow of said gas in said cavity about said axis,

maintaining the gas pressure at said axis at at least 100 p.s.i.a.,

maintaining the pressure of said gas radially-outwardly from said are in said cavity substantially greater than 100 p.s.i.a. and sufficiently high to stabilize said are along said axis and to constrict said are to a cross-sectional area smaller than it would normally occupy in space, and draining said gas continuously from said cavity,

transmitting directly through said wall the light generated by said are.

4. Apparatus for creating and transmitting high-intensity light, which comprises:

a transparent tube formed of heat-resistant material 'which is highly transmissive to lightradiati'on, first and second electrode assemblies inserted into opposite ends of said tube and closing said ends whereby a pressure chamber is defined therebetween,

at least one of said electrode assemblies having a base portion adjacent the interior surface of said tube,

said base portion having formed therethrough a plurality of gas-inlet passages which are tangential thereto whereby to effect vortical flow of the gas in said tube about said axis,

said electrode assemblies having arcing portions at the axis of said tube and spaced from each other a distance substantially smaller than the inner diameter of said tube and between 3 millimeters and 20 millimeters,

one only of said arcing portions having a gas-discharge passage therethrough along said axis, gas-flow means to introduce a relatively cool inert gas through said inlet passages and to recirculate gas from said gas-discharge passage to said inlet passages,

said gas in said entire gas-flow means being under a pressure many times atmospheric and serving to maintain the pressure along said axis at at least 100 p.s.i.a. andto maintain the pressure adjacent said tube substantially higher than the pressure along said axis, means to apply a positive D.C. voltage to said one arcing portion and a negative D.C. voltage to the other arcing portion,

said voltage being sufficiently high to maintain an are between said arcing portions along said axis, and means to pass water through said electrode assemblies to cool the same.

References Cited UNITED STATES PATENTS Hewitt 31329 X Miller 250-499 Wittlinger 250199 Beese 250 -199 Clark 313-231 Touvet 250199 Dana et a1 313-231.5 X Orbach 313-231 Gage 313231.5 X DeMaine 313-231 Gage et al 313-2315 X Mu tschler 250199 Rosener 313-231 X JAMES w. LAWRENCE, Primary Examiner.

P. C. DEMEO, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CQRRECTION Patent No. 3,405,314 vOctober 8, 1968 Delbert G. Van Ornum et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, line 53, cancel Signed and sealed this 10th day of March 1970.

(SEAL) Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer "and; line 54, after "cavity, insert and 

1. APPARATUS FOR GENERATING HIGH-INTENSITY LIGHT, COMPRISING: WALL MEANS TO DEFINE AN ARC CHAMBER, AT LEAST A MAJOR PORTION OF SAID WALL MEANS BEING A SURFACE OF REVOLUTION ABOUT A CENTRAL AXIS, AT LEAST A PORTION OF SAID WALL MEANS BEING LIGHTTRANSMISSIVE TO PERMIT LIGHT TO EMANATE FROM SAID CHAMBER, PASSAGE MEANS INCLINED RELATIVE TO SAID AXIS TO INTRODUCE DIRECTLY AND GENERALLY TANGENTIALLY INTO SAID CHAMBER, FOR FLOW VORTICALLY ABOUT SAID AXIS, A RELATIVELY COOL, INERT GAS HAVING A PRESSURE OF AT LEAST 100 P.S.I.A. AT SAID AXIS, MEANS TO DISCHARGE GAS FROM SAID CHAMBER ALONG SAID AXIS, AND MEANS TO CREATE IN SAID CHAMBER ALONG AT LEAST A PORTION OF SAID AXIS A HIGH-CURRENT ELECTRIC ARC OR DISCHARGE, SAID ARC OR DISCHARGE BEING STABILIZED BY SAID GAS AND GENERATING LIGHT FOR TRANSMISSION THROUGH SAID LIGHT-TRANSMISSIVE PORTION OF SAID WALL MEANS. 